Timing of the volcanism of the southern Kivu province: implications for the evolution of the western branch of the East African Rift system

Pasteels, Paul; Villeneuve, M.; Paepe, Paul De; Klerkx, J.

doi:10.1016/0012-821x(89)90152-0

Cited by 55 publications

(24 citation statements)

References 8 publications

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“…In the late Miocene (c. 7.5 Ma), major rifting took place in the Western branch of the EARS (Pasteels et al, 1989), with associated culmination of volcanic activity. The uplift rate of the Congo basin reached a maximum in the c. 11 to 5 Ma interval (Lavier et al, 2001;Guillocheau et al, 2015).…”

Section: Cenozoic Regional Geodynamic Contextmentioning

confidence: 99%

The age of supergene manganese deposits in Katanga and its implications for the Neogene evolution of the African Great Lakes Region

Putter

Ruffet

Yans

et al. 2015

Ore Geology Reviews

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International audienceSupergene manganese deposits commonly contain K-rich Mn oxides with tunnel structure, such ascryptomelane, which are suitable for radiometric dating using the 39Ar–40Ar method. In Africa, Mn depositshave been dated by this method for localities in western and southern parts of the continent, whereas onlysome preliminary data are available for Central Africa. Herewe present new39Ar–40Ar ages for Mnoxide samplesof the Kisenge deposit, in southwestern Katanga, Democratic Republic of the Congo. The samples represent supergeneMn oxide deposits that formed at the expense of primary Paleoproterozoic rhodochrosite-dominatedcarbonate ores. Main phases of Mn oxide formation are dated at c. 10.5 Ma, 3.6 Ma and 2.6 Ma for a core thatcrosses a mineralized interval. The latter shows a decrease in age with increasing depth, recording downwardpenetration of a weathering front. Surface samples of the Kisenge deposits also record a ≥c.19.2 Ma phase, aswell as c. 15.7 Ma, 14.2 Ma and 13.6 Ma phases. The obtained ages correspond to distinct periods of paleosurfacedevelopment and stability during the Mio-Pliocene in Katanga. Because Katanga is a key area bordered to theNorth by the Congo Basin and to the East by the East African Rift System, these ages also provide constraintsfor the geodynamic evolution of the entire region. For the Mio-Pliocene, the Kisenge deposits record ages thatare not systematically found elsewhere in Africa, although the 10.5–11 Ma event corresponds to a roughly simultaneousevent in the Kalahari Manganese Field, South Africa. The rest of the Katanga paleosurface record differssomewhat fromrecords for other parts of Africa, forwhich older, Eocene ages have been obtained. This differenceis most probably related to the specific regional geodynamic context: uplift of the East African Plateau, with associatederosion, and the opening of the East African Rift System at c. 25 Ma are events whose effects, in thestudy area, interfere with those of processes responsible for the development of continent-wide paleosurfaces

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Section: Cenozoic Regional Geodynamic Contextmentioning

confidence: 99%

The age of supergene manganese deposits in Katanga and its implications for the Neogene evolution of the African Great Lakes Region

Putter

Ruffet

Yans

et al. 2015

Ore Geology Reviews

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“…Magmatic activity in other parts of northern Kenya began ∼30 Ma (Morley et al 1992;Ritter & Kaspar 1997), although volcanism started ∼15 Ma in the central portion of the Kenya rift, at ∼12 Ma in southern Kenya (Morley et al 1992;Hendrie et al 1994;Mechie et al 1997) and at about 8 Ma in northern Tanzania (Dawson 1992;Foster et al 1997). Volcanism in the western branch began ∼12 Ma (Ebinger 1989;Pasteels et al 1989;Kampunzu et al 1998). Timing of plateau formation in East Africa remains poorly constrained, although there is evidence for Shear wave velocity beneath Africa 125 localized Neogene uplift along the flanks of some rift valleys (e.g.…”

Section: B a C Kg Ro U N D 21 The Geology Of East Africamentioning

confidence: 99%

Upper mantle shear wave velocity structure beneath the East African plateau: evidence for a deep, plateauwide low velocity anomaly

Adams

Nyblade

Weeraratne

2012

Geophysical Journal International

114

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SUMMARY The shear wave velocity structure of the upper mantle beneath the East African plateau has been investigated using teleseismic surface waves recorded on new broadband seismic stations deployed in Uganda and Tanzania, as well as on previously deployed stations in Tanzania and Kenya. Rayleigh wave phase velocities at periods between 20 and 182 s, measured with a two‐plane wave method, have been used to create phase velocity maps, and dispersion curves extracted from the maps have been inverted to obtain a quasi‐3‐D shear wave velocity model of the upper mantle. We find that phase velocities beneath the Tanzania Craton and areas directly north and west of the craton are faster, at all periods, than those beneath the Western and Eastern branches of the East African Rift System. At periods <50 s, the western branch is slower than the Eastern Branch, but at periods greater than 50 s, this relationship is reversed. Anisotropy is found at all periods, with a generally north–south fast polarization direction. The shear wave velocity model shows a seismically fast lithosphere (lid) beneath the Tanzania Craton to depths between 150 and 200 km. The fast velocities in this depth range extend to the north beneath the Uganda Basement Complex and to the east beneath the northern Tanzania divergence zone, indicating that these regions together form a rigid block around which rifting has occurred within weaker mobile belt lithosphere. The Eastern and Western branches are slower than the craton at lithospheric mantle depths, and both branches show variable structure in the upper 200 km of the mantle, with the lowest velocities found beneath areas of Cenozoic volcanism. At depths greater than ∼225 km, a low velocity anomaly is present beneath the entire East African plateau that may extend into the mantle transition zone. Velocities in the low velocity region are reduced by ≥10 per cent relative to lid velocities, and if attributed only to temperature variations, would represent an unrealistic thermal perturbation of >400 K. Consequently, it is likely that the velocity reduction reflects a combination of thermal and compositional changes, and also possibly the presence of partial melt. The width and thickness of the low velocity anomaly is greater than typically expected for a plume head and is more easily attributed to an upward continuation of the lower mantle African superplume structure into the upper mantle.

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“…In the present study, however, we consider only the southern part of the Eastern branch from northern Kenya to north‐eastern Tanzania. The Western branch (Bauer et al., ; Daly, Chorowicz, & Fairhead, ; Ebinger, ; Morley, Cunningam, Wescott, & Harper, ; Pasteels, Villeneuve, De Paepe, & Klerkx, ) is composed of the Albert‐Edward, Kivu and Tanganyika‐Rukwa rifts, oriented in NE–SW, N–S and NW–SE directions, respectively, depicting an arcuate map‐trace along the western side of the Tanzanian craton (Figure ). The southern prolongation of the Western branch is represented by the Malawi rift (Laó‐Dávila, Al‐Salmi, Abdelsalam, & Atekwana, ; Ring, Betzler, & Delvaux, ), which is aligned on a N–S trend extending from the Rungwe volcanic province (southern Tanzania) to the Urema graben (Mozambique).…”

Section: Introductionmentioning

confidence: 99%

Non‐uniform splitting of a single mantle plume by double cratonic roots: Insight into the origin of the central and southern East African Rift System

et al. 2018

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Timing of the volcanism of the southern Kivu province: implications for the evolution of the western branch of the East African Rift system

Cited by 55 publications

References 8 publications

The age of supergene manganese deposits in Katanga and its implications for the Neogene evolution of the African Great Lakes Region

The age of supergene manganese deposits in Katanga and its implications for the Neogene evolution of the African Great Lakes Region

Upper mantle shear wave velocity structure beneath the East African plateau: evidence for a deep, plateauwide low velocity anomaly

Non‐uniform splitting of a single mantle plume by double cratonic roots: Insight into the origin of the central and southern East African Rift System

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